Background:After a stroke, the control of the trunk muscle may be severely impaired. Due to the importance of trunk control in complex daily postures, the ability to adopt a correct sitting posture is considered a determinant of the recovery of independent function after a stroke.Objects:The purposes of this study were to compare differences in buttock pressure between the left and right sides of hemiplegic patients and differences in their pelvic tilting angles (sagittal and coronal planes) after sitting training with visual biofeedback (VBF) in real time.Methods:Twenty-two individuals with unilateral strokes (11 left-side and 11 right-side hemiplegic stroke patients) participated in this study. Buttock pressure was measured using a pressure mat, and pelvic angles were measured using a palpation meter.Results:The asymmetry of pressure between the right and left (first and third chamber) sides was significantly decreased after the VBF training. The measurements obtained using the palpation meter revealed a significant decrease in the pelvic angles pre- versus post-intervention.Conclusion:VBF training may be distribute a patient’s buttock pressure equally while in a sitting posture and increase the length of time a stroke patient can maintain a symmetrical sitting posture. It can also improve pelvic control while sitting in a neutral position.

Asymmetric sitting posture may cause asymmetric buttock pressure and unilateral low back pain (LBP). The purpose of this study was to compare the differences of buttock pressure between both sides, and pelvic angle (sagittal and coronal planes) during typing in a sitting position on a pressure mat (Baltube) in individuals with and without unilateral LBP. Ten subjects with unilateral LBP and ten subjects without unilateral LBP were recruited for this study. Buttock pressure was measured using a pressure mat and pelvic angles were measured using a palpation meter. The subjects performed typing in a sitting posture for 30 minutes. Pressure data were collected and averaged at initial term (from start to first minutes) and final term (last minutes of 30 minutes). Angles of pelvic tilting were measured after 30 minutes typing. Pressure asymmetry values (difference in pressure between both sides) were calculated at the initial and final terms. A two-way analysis of variance was used to compare the differences between the initial and final pressure asymmetry values in subjects with and without unilateral LBP. An independent t-test was applied to compare the pelvic tilt angles between the two groups. To compare the change of pressure from the initial term to the final term between the symptomatic and asymptomatic sides in the unilateral LBP group, a paired t-test was applied. In the unilateral LBP group, the pressure asymmetric value at the final term was significantly greater than that of the initial term (p<.05). The angle of pelvic tilting in coronal plane was significantly greater in the unilateral back pain group compared to the without unilateral LBP group (p<.05), however, there was no significant difference in the angle of pelvic tilting in the sagittal plane between the two groups (p>.05). In the unilateral LBP group, the change of pressure from the initial term to the final term was significantly less in the symptomatic side (-6.90 ㎜Hg) than the asymptomatic side (5.10 ㎜Hg). This asymmetric sitting posture may contribute to unilateral LBP in the sitting position. Further studies are needed to determine if asymmetric weight bearing in sitting causes unilateral LBP or if unilateral back pain causes asymmetric weight bearing, and if the correction of asymmetric weight bearing in sitting can reduce unilateral LBP.

The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on the muscle activity of lumbar stabilizers and the angle of pelvic lateral tilting during hip abduction in side lying. Twenty healthy male subjects with no medical history of lower extremity or lumbar spine disorders were recruited for the study. Subjects randomly performed preferred hip abduction (PHA) and hip abduction with contralateral hip adduction in side lying. The muscle activities of the dominant side rectus abdominis, external oblique, internal oblique, quadratus lumborum, gluteus medius, and non-dominant side hip adductor longus were measured during PHA and CHA by using a surface electromyography (EMG) system. Pelvic lateral tilting motion was measured by using a three-dimensional motion analysis system. Data on EMG and pelvic motion were collected at the same time during PHA and CHA. A paired t-test was used to compare EMG activity and the angle of pelvic lateral tilting in the two exercises. The study found that the EMG activities of all muscles were more increased significantly in CHA than PHA condition. The angle of pelvic lateral tilting was more decreased significantly in CHA than PHA condition. These findings suggest that CHA could be recommended as a hip abduction exercise for activating lumbar stabilizers and decreasing compensatory pelvic lateral tilting motion.

The purpose of this study was to determine the effect of contralateral hip adduction (CHA) on thickness of lumbar stabilizers during hip abduction in side-lying. Twenty healthy subjects without back pain were recruited for this study. The thickness of transverse abdominis (TrA), internal oblique (IO) and quadratus lumborum (QL) were measured by ultrasonography. Pelvic lateral tilting motion was measured using a three-dimensional motion analysis system. Measurements were performed at rest position (RP), preferred hip abduction (PHA) and abduction with contralateral hip adduction (CHA) in side-lying at the end of expiration. During the measurements, subjects were asked to maintain steady trunk alignment without hand support. Thickness of TrA and IO was significantly greater in CHA than in PHA and RP conditions. There was no significant difference in thickness of TrA and IO between PHA and RP conditions. Medio-lateral (M-L) thickness of QL was not significant between PHA and CHA conditions. Anterio-posterior (A-P) thickness of QL in PHA and CHA significantly decreased compared to RP condition. Angle of pelvic lateral tilting was significantly decreased in CHA compared to PHA condition. In conclusion, CHA can be recommended for increasing trunk stability without compensatory pelvic motion during hip abduction exercise in side-lying.

The purpose of this study was to analyze the effects of three different pelvic tilts on sit-to-stand ativities and to suggest a new therapeutic approach for movement reeducation in patients who have difficulty with sit-to-stand activities. The three different pelvic tilts were: (1) comfortable pelvic tilt sit-to-stand (CPT STS), (2) posterior pelvic tilt sit-to-stand (PPT STS) and (3) anterior pelvic tilt sit-to-stand (APT STS). To analyze the kinematic component of STS, a motion analysis system (Zebris) was applied to the ankle, knee, hip joint, and thigh-off area. Also, to determine the onset time of muscle contraction, surface electrodes were placed to the rectus femoris muscle (RF), the vastus lateralis muscle (VL), the biceps femoris muscle (BF), the tibialis anterior muscle (TA), the gastrocnemius muscle (GCM), and the soleus muscle (SOL). One-way repeated ANOVA was used for the statistical analysis. First, significant differences were found in kinematic variables for the hip, knee, ankle joint, and thigh-off among the three activities. Second, there was significant difference in muscle activation pattern in TA. VL. and BF among three activities. In conclusion, the findings of this study suggest the following evaluative and therapeutic approach for STS activity: (1) Changes in knee and ankle joints should be prioritized and recruitment order differences in VL and RF can be generated to accomplish abnormal STS activity. (2) APT STS can be introduced for movement efficiency and functional advantage when abnormal STS is treated.

The purpose of this study was to analyze the effects of three different pelvic tilts on a sit-to-stand (STS) and to suggest a new assessment approach based on biomechanical analysis. The three difrent pelvic tilts were: (1) comfortable pelvic tilt sit-to-stand (CPT STS), (2) posterior pelvic tilt sit-to-stand (PPT STS) and (3) anterior pelvic tilt sit-to-stand (APT STS). To determine the onset time of muscle contraction surface electrodes were applied to the rectus femoris muscle (RF), vastus lateralis muscle (VL), biceps femoris muscle (BF), tibialis anterior muscle (TA), gastrocnemius muscle (GCM), and soleus muscle (SOL). The ICC was used for functional linkage analysis. The findings of this study were as follows. First, significant differences were found in kinematic variables and in muscle activation pattern among the three activities. Second, the results of functional integrated analysis revealed that recruited muscle activation patterns changed when the thigh-off was viewed as a reference point. Third, there were independent functional units between the thigh-off and the VL and between the thigh-off and the RF in the functional linkage analysis. The VL and RF acted as prime mover muscles, and more postural adjustment muscle recruitment was required as the demand of postural muscle control increased (PPT STS, APT STS, and CPT STS in order). In conclusion, the findings of this study suggest the following evaluative and therapeutic approach for STS activity. APT STS can be introduced for movement efficiency and functional advantage when abnormal STS is treated. However, excessive APT would change the muscle activation patterns of BF and SOL and require additional postural muscle control to cause abnormal control patterns.

The objective of this study was to identify the effects of pelvic tilting exercise on gait patterns of hemiplegic patients. The subjects of this study were 31 hemiplegic in- and out-patients of the Rehabilitation Hospital, Yonsei University Medical Center, from September 24, 1997 through November 5, 1997. Pre- and post-treatment change in gait patterns were measured using a ink foot-print. The data were analyzed by the paired t-test, one-way ANOVA, and independent t-test. The findings were as follows: The difference in gait patterns between pre- and post-treatment was statistically significant, with an increase in gait velocity to 7.98 cm/sec post-treatment; an increase in cadence to 7.29 steps/min; a narrowing of the base of support to 1.33 cm; an increase in step length of 3.92 cm on the less affected side and 3.73 cm on the more affected side; an increase in stride length of 5.82 cm on the less affected side and 5.92 cm on the more affected side(statistically not significant in foot angle). In relation to sex, age, cause of stroke, and laterality of paralysis, the difference in gait patterns between pre- and post-treatment was not statistically significant. Where there was no significant difference of the effects of pelvic exercise regarding the degree of spasticity, the presence of a decrease in proprioception, and the duration of treatment. In conclusion, hemiplegic pelvic tilting exercise was found to have transmitting positive effect in improving gait patterns.

The purposes of this study were to examine the effect of two different pelvic alignments and the Valsalva maneuver on electromyographic (EMG) activity of the erector spinae during squat lifting and lowering, and to find an efficient method for squat lifting and lowering. Twenty hea1thy men in their twenties lifted and lowered loads using four different methods: 1) anterior pelvic tilt position with the Valsalva maneuver, 2) anterior pelvic tilt position without the Valsalva maneuver, 3) posterior pelvic tilt with the Valsalva maneuver, 4) posterior pelvic tilt without the Valsalva maneuver. The EMG activity of erector spinae was recorded during both lifting and lowering with each method. The EMG activity of each individual was normalized to EMG activity produced by muscle during maximal voluntary contraction. Two-way analysis of variance for repeated measures () was used to analyze the effect of the two factors: 1) pelvic tilt position (anterior pelvic tilt, posterior pelvic tilt), 2) the Valsalva maneuver (with and without). Analysis was performed separately for the lifting and lowering. The results were as follows: 1) EMG activity of erector spinae was greater when the pelvis was tilted anteriorly than when the pelvis was tilted posteriorly during squat lifting and squat lowering. 2) There was no difference between EMG activity of erector spinae with the Valsalva maneuver and EMG activity of erector spinae without the Valsalva maneuver during squat lifting and squat lowering. These results suggest that the greater EMG activity of erector spinae with an anterior pelvic tilt position during squat lifting and squat lowering may ensure optimal muscular support for the spine while handling loads, but the Valsalva maneuver may have less effect on erector spinae.